The Trend extension is used to trend LonWorks point data. It monitors and records the changes in behavior of an individual attribute and displays the results in both graphical and tabular formats.
When trending LonWorks network device objects using samples taken at fixed predetermined intervals, the initial trend period results may differ from the expected trend start time. LonWorks network status reporting for trend objects reports trend data correctly but always remains one interval cycle behind the actual field value. For example, in a 60-minute cycle where the value always increments by 2, if the current Present Value of the object is 0, then 0 is logged in the trend even through the field has a value of 72. The LonWorks object is then polled, and the Present Value updates to 72. After 60 minutes, the field value changes to 74, but the trend sample logs the current Present Value, which is 72. The only exception to this pattern is if the LonWorks object is polled by some other means. See Trend process in this section for more information.